Method of artificially producing radioactive substances



. 1,644,370 9 A. GASCHLER METHOD OF ARTIFICALLY PRODUCING RADIOACTIVESUBSTANCES Filed Sept. 4, 1924 GaSc/qlew Patented Oct. 4, 1927.

UNITED STATES 1,644,370 PATENT OFFICE.

ALOIS GASCHLER, OF BERLIN, GERMANY.

METHOD OF ARIIT'ICIALLY PRODUCING RADIOACTIVE SUBSTANCES.

- Application filed September 4, 1924, Serial No. 735,962, and inGermany April 20, 1923.

The object of this invention is to transform materials of relativelylow. radioactivity into materials of relatively high radioactivity andin general to increase the radioactivity of such'materials.

Another object of my invention is to increase the radioactivity ofuranium and thorium.

Another object of my invention is to accelerate to a hi hdegree the veryslow spontaneous trans ormation of uranium and thorium. a

In general, in the process of my invention, a small quantity of metal tobe transformed is heated to a high temperature under high pressure in anenclosed chamber. The metallic vapor is dissociated, and is exposedeither to high electro-static, uni directional potentials or touni-directional currents at igh potentials. The volume of the chamber isusually large in proportion to the normal volume of the material to betransformed. The currents and high potentials may be employed concurrentwith the heating step. I

ave used on the average approximately 100 kilowatt seconds of electricalenergy to produce 1 gram of uranium or thorium.

' In order to producea very high pressure, while heating the metal andto avoid as much as possible the loss of energy by the esca e of heat,such as radiation, the metal is ormed into a thin filament weighingabout 1 gram. The filament is fixed inside a channel formed in a mass ofinsulating material, such as massive quartz, granite, steatite or otherstone or mineral. The two ends of the filament are attached to two largemetallic disks which act also as closing means for the channel. Thesedisks bear clamps to which leads for the source of current may beattached. The duration of the current is usually 1-2 seconds. Aftercooling the metal may be regained either by mechanical or chemicalmeans.

Tested by difierent methods the product obtained proves to beconsiderably more radioactive than the product before transformation.This process can also be applied to the rational transformation of otherelements.

The efiiciency of the transformation is all the greater the higher thepotential of the current. The efficiency is also higher, the more thedissociated vapor comes in contact with the pole faces. In operatingthis process it is advisable therefore to employ not onl a heatingcurrent of low voltage and big intensity but also a current of smallintensity and high voltage. It is therefore advisable to insert into thechamber a second pair of electrodes of large surface which is connectedto a high tension circuit. A Crooks tube and a rectifier tube may beemployed in this circuit as a high tension resistance.

In operating on a large scale, instead of using metallic filaments, themetal to be transformed is introduced into the chamber containing theelectric are via a valve and is also removed from this chamber via avalve.

Reference may be had to the accompanying figure for an apparatus capableof carrying out my process.

Referring to this drawing, a is an earthenware iacket or sheathing, inwhich there is provi ed a cavity. or hollow space I; for the receptionof the metal to be transformed which metal passes through the cavity 6in the form of a filament a or, if mercury is involved, fills thepassage 6 so as to form a two metal plates d and e are fitted with thenecessary current terminals.

The above is to be taken as merely illustrative of my invention and thebest mode of operating the same and not as limiting the invention whichis defined in the appended claims.

1. A process for increasing the radioactivity of materials whichcomprises heating the same to a high temperature and pressure andsubmitting the heated material to the influence of a high potentialcurrent.

2. A process for increasing the radioactivityof materials whichcomprises heating the same to a high temperature and pressure in arelatively large chamber and submitting the said material to a highpotential unidirectional current.

3. A process for increasing the radioactivity of materials whichcomprises heating said materials to a high temperature by means of anelectric current of low voltage and high intensity and subjectin saidheated ma-. terials to a current of high voltage and low intensity.

4. A process for increasing the radioactivity of materials whichcomprises heating said materials to a high temperature to vaporize'saidmaterial and submitting said vapors to the action of. a high tensioncur- These rent passing between electrodes of relatively large electrodesurfaces and submitting said vapors to contact with saidelectrodes.

5. A process for theincreasing radioactiv- 6 ity of materials whichcomprises vaporizing said materials by heating said materials to a hightemperature and at a high pressure by means of a current of low voltageand high intensity and submitting said vapors to contact with relativelylarge electrodes and passing a high tension low intensity currentbetween said electrodes.

' In testimony whereof I aflix my signature.

DB. ALOIS GASCHLER.

